Isolation type direct-current detection circuit with preceding-stage protection function

Abstract

The invention provides an isolation type direct-current detection circuit with a preceding-stage protection function. The direct-current detection circuit comprises a preceding-stage protection circuit, an optocoupler isolation circuit and a first-stage amplification circuit; an input signal is connected with the input end of the preceding-stage protection circuit; the output end of the first-stage amplification circuit is connected with the input end of a first-stage filter circuit and the input end of a second-stage amplification circuit; the output end of the first-stage filter circuit is connected with a first channel of a microcontroller; the output end of the second-stage amplification circuit is connected with the input end of the second-stage filter circuit; and the output end of the second-stage filter circuit is connected with a second channel of the microcontroller. The preceding-stage protection circuit is adopted for a preceding stage, the optocoupler isolation circuit anda signal amplification circuit are adopted for an intermediate stage, and finally, a low-pass filter circuit is adopted, so that direct-current detection is realized; under a limit short circuit condition of a circuit breaker, the detection circuit can be protected from being damaged, and an isolation unit is adopted to realize the isolation of a strong current and a weak current, so that the personal and line safety of a weak current area is guaranteed; and meanwhile, the accuracy of a detection result is improved through filtering processing.

Description

technical field [0001] The invention relates to an isolated DC current detection circuit with pre-stage protection, which is mainly used for the current detection of DC molded case circuit breakers and belongs to the technical field of low-voltage electrical appliances. Background technique [0002] DC molded case circuit breakers are mainly responsible for overload and short circuit protection of transmission and distribution lines and electrical equipment. With the development of intelligent ships and the continuous improvement of the level of electrical intelligence of ships, the DC molded case circuit breaker has put forward the requirement of remote parameter high-precision monitoring function. These monitored parameters include the monitoring of current. [0003] At present, there are mainly two kinds of existing direct current detection methods. The first is the direct measurement method, which uses a shunt connected in series to the main circuit to convert the DC cu...

AI Technical Summary

Problems solved by technology

If there are no corresponding protection measures, it will cause the detection circuit to burn out

Since the shunt is directly connected to the main circuit when it is working, if there is no corresponding isolation measure, the high voltage of the main circuit will be connected to the detection circuit, which may endanger the safety of personnel.

The current measurement of the circuit breaker requires a wide range, which cannot be completed with a single channel, and due to the complexity of the application, no filtering measures are taken before the sampling signal enters the microcontroller for processing, resulting in a large deviation of the measurement data

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